leaving mem= off doesnt fix it. Looks like 2.4.18 doesnt even try to map it. As before, I have attached the entire dmesg's to this email ==> dmesg-2.4.18-4GB-nomem <== Linux version 2.4.18-4GB (root@mcp) (gcc version 2.95.4 20011002 (Debian prerelease)) #3 SMP Mon Apr 7 05:29:01 EDT 2003 BIOS-provided physical RAM map: BIOS-88: 0000000000000000 - 000000000009f000 (usable) BIOS-88: 0000000000100000 - 0000000001000000 (usable) found SMP MP-table at 000f4ff0 hm, page 000f4000 reserved twice. hm, page 000f5000 reserved twice. hm, page 000fb000 reserved twice. hm, page 000fc000 reserved twice. On node 0 totalpages: 4096 ==> dmesg-2.4.23-4GB-nomem <== Linux version 2.4.23-4GB (root@mcp) (gcc version 2.95.4 20011002 (Debian prerelease)) #1 SMP Wed Dec 3 10:28:26 EST 2003 BIOS-provided physical RAM map: BIOS-88: 0000000000000000 - 000000000009f000 (usable) BIOS-88: 0000000000100000 - 0000000001000000 (usable) 0MB HIGHMEM available. 16MB LOWMEM available. found SMP MP-table at 000f4ff0 hm, page 000f4000 reserved twice. hm, page 000f5000 reserved twice. hm, page 000fb000 reserved twice. --- Forwarded Message --- From: "Jason Walker" To: linux-kernel@vger.kernel.org Sent: Thu, 04 Dec 2003 13:10:31 -0500 Subject: Unable to address 1GB RAM in 2.4.19 or later I have run into an issue where I cannot address all of my 1GB of RAM. 2.4.18 was the last kernel that can address all 1GB. All kernels since then appear to only be able to address 16mb of ram if I use the 4GB himem kernel option. Here is a snip of the dmesg on the working 2.4.18 and broken 2.4.23 kernels: ==> dmesg-2.4.18-4GB <== Linux version 2.4.18-4GB (root@mcp) (gcc version 2.95.4 20011002 (Debian prerelease)) #3 SMP Mon Apr 7 05:29:01 EDT 2003 BIOS-provided physical RAM map: BIOS-88: 0000000000000000 - 000000000009f000 (usable) BIOS-88: 0000000000100000 - 0000000001000000 (usable) 128MB HIGHMEM available. found SMP MP-table at 000f4ff0 hm, page 000f4000 reserved twice. hm, page 000f5000 reserved twice. hm, page 000fb000 reserved twice. hm, page 000fc000 reserved twice. ==> dmesg-2.4.23-4GB <== Linux version 2.4.23-4GB (root@mcp) (gcc version 2.95.4 20011002 (Debian prerelease)) #1 SMP Wed Dec 3 10:28:26 EST 2003 BIOS-provided physical RAM map: BIOS-88: 0000000000000000 - 000000000009f000 (usable) BIOS-88: 0000000000100000 - 0000000001000000 (usable) user-defined physical RAM map: user: 0000000000000000 - 000000000009f000 (usable) user: 0000000000100000 - 0000000001000000 (usable) 0MB HIGHMEM available. 16MB LOWMEM available. found SMP MP-table at 000f4ff0 What concerns me about these is that even in the 2.4.18 kernel it only reports 128MB HIGHMEM in the dmesg, even though it does see all 1GB when booted (free confirms this). I am thinking 2.4.18 isnt detecting something properly either, but is only a problem in 2.4.19 and later. Both are SMP kernels. The hardware is a Compaq Proliant 5000R, quad pentium pro 200mhz (256k cache models). Any thoughts on this? Is there any other information needed to address this issue? Please let me know what I can do to assist in correcting this bug.